MIB-1 expression in odontogenic epithelial rests, epithelium of healthy oral mucosa and epithelium of selected odontogenic cysts. An immunohistochemical study.

The aim of this study is to investigate the proliferative potential of rests of odontogenic epithelium found in follicles of unerupted teeth, epithelium of oral mucosa and epithelial linings of various odontogenic cysts. MIB-1 expression was studied in the rests of odontogenic epithelium (n=10), healthy oral mucosa (n=10), odontogenic keratocysts (n=10) and other odontogenic cysts (n=10) using an avidin-biotin peroxidase technique on paraffin sections. The number of positively stained cells was counted on 10 representative areas of epithelium using a x40 objective. The average number of MIB-1 positive cells in each group was calculated. No MIB-1 positive cells were seen in the rests of odontogenic epithelium. The mean numbers of MIB-1 positive cells detected within the epithelium of oral mucosa, and of radicular and dentigerous cysts were similar. The number of MIB-1 positive cells was found to be increased in the presence of marked inflammatory cell infiltration. The highest number of MIB-1 positive cells was seen in the keratocysts. These findings suggest that removal of an unerupted tooth to prevent the possibility of neoplastic transformation of rests of odontogenic epithelium is not a justifiable rationale.

Adenosine deaminase and 5'-nucleotidase activities in saliva from patients with oral and laryngeal cancer.

OBJECTIVE: The aim of this study was to evaluate saliva's activities of adenosine deaminase (ADA) and 5'-nucleotidase (5'-NT) enzymes and their utility as diagnostic and therapeutic markers in oral and laryngeal cancer. MATERIALS AND METHODS: Pre- and post-operative saliva's activities of ADA and 5'-NT enzymes were measured in patients with squamous cell oral (n = 10) and laryngeal cancer (n = 17) and compared with control saliva samples (n = 19). RESULTS: The ADA was found to be lower in saliva of the patients with oral cancer compared with the laryngeal cancer and controls. However, no significant differences were found between pre- and post-operative values for both enzymes in the patient groups. We also could not find statistically significant differences between saliva's activities of 5'-NT in patients and control subjects. CONCLUSIONS: Low activity of ADA observed in saliva of the patients with oral cancer has been suggested as a compensatory mechanism against rapid purine and DNA metabolism in cancer cells. The current study does not support the hypothesis that saliva's activities of these enzymes may be used as additional diagnostic and prognostic cancer markers.